package org.zz.lucene_anlyzer;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.core.LowerCaseFilter;
import org.apache.lucene.analysis.core.StopFilter;
import org.apache.lucene.analysis.en.EnglishPossessiveFilter;
import org.apache.lucene.analysis.en.PorterStemFilter;
import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.analysis.standard.StandardFilter;
import org.apache.lucene.analysis.standard.StandardTokenizer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.util.CharArraySet;
import org.apache.lucene.util.Version;

/**
 * {@link Analyzer} for English.
 */
public final class ZEnglishAnalyzer extends ZStopwordAnalyzerBase {
  private final CharArraySet stemExclusionSet;
  private int limitedTokenCount;
   
  /**
   * Returns an unmodifiable instance of the default stop words set.
   * @return default stop words set.
   */
  public static CharArraySet getDefaultStopSet(){
    return DefaultSetHolder.DEFAULT_STOP_SET;
  }
  
  /**
   * Atomically loads the DEFAULT_STOP_SET in a lazy fashion once the outer class 
   * accesses the static final set the first time.;
   */
  private static class DefaultSetHolder {
    static final CharArraySet DEFAULT_STOP_SET = StandardAnalyzer.STOP_WORDS_SET;
  }

  /**
   * Builds an analyzer with the default stop words: {@link #getDefaultStopSet}.
   */
  public ZEnglishAnalyzer(Version matchVersion,int limitedTokenCount) {
    this(matchVersion, DefaultSetHolder.DEFAULT_STOP_SET,limitedTokenCount);
  }
  
  /**
   * Builds an analyzer with the given stop words.
   * 
   * @param matchVersion lucene compatibility version
   * @param stopwords a stopword set
   */
  public ZEnglishAnalyzer(Version matchVersion, CharArraySet stopwords,int limitedTokenCount) {
    this(matchVersion, stopwords, CharArraySet.EMPTY_SET,limitedTokenCount);
  }

  /**
   * Builds an analyzer with the given stop words. If a non-empty stem exclusion set is
   * provided this analyzer will add a {@link KeywordMarkerFilter} before
   * stemming.
   * 
   * @param matchVersion lucene compatibility version
   * @param stopwords a stopword set
   * @param stemExclusionSet a set of terms not to be stemmed
   */
  public ZEnglishAnalyzer(Version matchVersion, CharArraySet stopwords, CharArraySet stemExclusionSet,int limitedTokenCount) {
    super(matchVersion, stopwords,new ClearSetReuseStrategy());
    this.stemExclusionSet = CharArraySet.unmodifiableSet(CharArraySet.copy(
        matchVersion, stemExclusionSet));
    this.limitedTokenCount = limitedTokenCount;
  }

  /**
   * Creates a
   * {@link org.apache.lucene.analysis.Analyzer.TokenStreamComponents}
   * which tokenizes all the text in the provided {@link Reader}.
   * 
   * @return A
   *         {@link org.apache.lucene.analysis.Analyzer.TokenStreamComponents}
   *         built from an {@link StandardTokenizer} filtered with
   *         {@link StandardFilter}, {@link EnglishPossessiveFilter}, 
   *         {@link LowerCaseFilter}, {@link StopFilter}
   *         , {@link KeywordMarkerFilter} if a stem exclusion set is
   *         provided and {@link PorterStemFilter}.
   */
  @Override
  protected TokenStreamComponents createComponents(String fieldName,
      Reader reader) {
    final Tokenizer source = new StandardTokenizer(matchVersion, reader);
    TokenStream result = new StandardFilter(matchVersion, source);
    // prior to this we get the classic behavior, standardfilter does it for us.
    if (matchVersion.onOrAfter(Version.LUCENE_31))
      result = new EnglishPossessiveFilter(matchVersion, result);
    result = new LowerCaseFilter(matchVersion, result);
    result = new StopFilter(matchVersion, result, stopwords);
    if(!stemExclusionSet.isEmpty())
      result = new KeywordMarkerFilter(result, stemExclusionSet);
    result = new PorterStemFilter(result);
    if(limitedTokenCount > 0)
    	result = new RestrictedTokenCountFilter(result,limitedTokenCount);
    return new TokenStreamComponents(source, result);
  }
  
  public static class ClearSetReuseStrategy extends ReuseStrategy{

	@Override
	public TokenStreamComponents getReusableComponents(String fieldName) {
		// TODO Auto-generated method stub
		TokenStreamComponents components = (TokenStreamComponents) getStoredValue();
		if(components != null && components.getTokenStream() != null)
			try {
				components.getTokenStream().reset();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		return components;
	}

	@Override
	public void setReusableComponents(String fieldName,
			TokenStreamComponents components) {
		// TODO Auto-generated method stub
		setStoredValue(components);
	}
	  
  }
  
  public static void main(String[] args) throws IOException {
//	  ZEnglishAnalyzer analyzer = new ZEnglishAnalyzer(Version.LUCENE_40,new CharArraySet(Version.LUCENE_40,FileUtil.ReadTXTFile("./res/EnglishStopWords.txt","UTF-8"),true),700);
//	  String str = "correlation methods;covariance matrices;electromagnetic wave scattering;MIMO radar;radar cross-sections;radar detection;radar tracking;MIMO radar target detection;parametric scattering correlation model;multiple-input multiple-output radars;radar performance;angular diversity;distributed antennas;radar cross-section;statistical MIMO radar;scattered signals;parametric model;scattering covariance matrix;";
//	  int count = 0;
//	  TokenStream tokenStream = analyzer.tokenStream("name", new StringReader(str));
//	  CharTermAttribute termAtt = tokenStream.addAttribute(CharTermAttribute.class);
//	  while(tokenStream.incrementToken()){
//		  System.out.println(termAtt.toString());
//	  } 
//	  analyzer.close();
  }
  
}
